Alternating-current generator



Nov. 2 T925- 1,604,986

W. E. GARITY ALTERNATING CURRENT GENERATOR Filed Oct. 7, 1921 2Sheets-Sheet 1 ATTORNEYS Nov. 2 1926. 'l",6 04,986

W. E. GARITY ALTERNATING CURRENT GENERATOR Filed 001',- 7, 1921 2Sheets-Sheet 2 Patented Nov. 2, 1926.

1,604,986 UNITED STATES PATENT OFFICE."

WILLIAM-E. GARI'I'Y, OF NEW YORK, N. Y ASSIGNOR '10 DE FOREST RADIO TELEPHONE AND TELEGRAPH DELAWARE.

ALTERNATING-CURRENT GENERATOR.

Application filed October 7, 1921.

This invention relates to means for generatin alternating currents, andmore articulafiy to sustain high frequency osci latin currents.

fihe object of the invention is to provide means which are simple instructure, highly eflicient in o ration, and economical of manufacture,or generating alternating currents, by means of the so-calledphotion orspaced electrode light series tube.

Further ob'ects of the invention Wlll appear more in 1y hereinafter.

The invention consists substantially in the construction, combination,location, and relative arran ement of parts, all as will be more fullyhereinafter set forth as shown by the accompanying drawings, and finallypointed out in the appended claims.

Referring to the drawings,-

-Fig. 1 is a diagrammatic view of an alternating current generatorsystem embodyin my invention.

Figs. 2 and 3 are views in elevation of a modified structure ofevacuated vessel employed in connection therewith.

F ig. 4 is a diagrammatic view illustrating a still further modifiedarrangement employed in accordance with my invention.

Figs. 5 and 6 show still further modified arrangements.

The same part is designated by the same reference numeral wherever itoccurs throughout the several views.

In the so-called photion tube, especially where the central portion isconstricted, exists a conducting column of gas which carries aconsiderable current between the cold electrodes at from five hundred toone thousand volts, provided the gas pressure is such as to give themaximum conductivity, pref erably from 0.2 to 5.0 millimeters ofmercur-y pressure. This column of conducting gas is extremely sensitiveto GlGGtIOStHtIO OIf electromagnetic influences when applied to thecontrol electrodes positioned either on the outside or the inside of thetube, and at various points thereon, particularly at its narrow orconstricted portion, or at either end away from the two main electrodeswhich are conducting the current through the tube. Referring to thedrawings, reference numeral 1 designates the glass tube containingtherein attenuated gas, for exams Serial No. 505,969.

COMPANY, 01 NEW YORK, N. Y.', A CORPORATION 01 I ple hydrogen, ordinaryair, or the like.

an 3 represent the main or current sup ly electrodes, preferably locatednear either end of the tube, and preferably, but not necessarlly, 1n theform of open ended cylinders of suitable metal, such as nickel,molybdenum, tungsten, etc., and freed of gas, and thoroughly clean. Therespective electrodes 2 and 3 are enclosed within the enlarged portionsof the tube which are connected together by the neck. portion 14, whichpreferably, but not necessarily, is of constricted cross section.Reference numeral 4 designates the control electrode, which may be, asin Fig. 1, a simple cylinder on the outside of the middle portion of thetube, or in the form of a disk, or the like, 4, located in a pocket 50blown in the tube, as in Fig. 2,

.or as in Fig. 3, this electrode may be in the form of a grid or mesh4", positioned transverse to the axis of the tube, and preferably in aslightly enlarged portion 50 thereof at its center, or the controlelectrode 4 may be located at either or both ends of the tube beyond themain electrode or electrodes as shown in Fig. 5.

The constricted portion 14 of the tube acts to concentrate the dischargepath or beam between the electrodes 2 and 3, thus increasing theinternal resistance of the tube, but

aiding (by means of an eflect analogous to the so-called pinch effect)in the tendency of the gas discharge to be interrupted or reduced atdesired intervals. 1

If now such a discharge tube as herein shown be connected across asuitable source of high tension either direct current or alternatingcurrent, but preferably direct current such as illustrated at 13, Fig.1, then a steady passage of current therethrou h is produced. If acircuit containing suitable inductance and capacity be connected to themain electrodes, oscillations or periodic fluctuations in the dischargethrough the gas column may be set up (as is well known, fior example inconnection with Geissler tubes). The period of such oscillations orpulsations depends in large measure on the amount of inductance andcapacity in the said attached circuit, but also to a certain degree onthe length, diameter, pressure, and nature of the gas column. Suchelectric oscillations or} pulsations, old in the art,

to employ a stopping condenser 10, prefer-' are, however, exceedinglyfeeble and unreliable in nature, particularly if their frequency be madehigh. I have found however that if a third or control electrode beprovided as herein shown, which control electrode is suitably connectedto a proper point in the oscillation circuit, then if at certaininstances in the oscillation cycle a sufliciently high transient E. M.F. is applied to said control electrode, the tendency of the directcurrent in the gas to more or less interrupt itself is very greatlyaided, with the result that the fluctuating or pulsating tendency isaided. Thus in Fig. 1 an oscillation circuit consisting of theinductance 8 and the capacity 11 is connected across the two mainelectrodes 2 and 3 of the discharge tube. In this circuit I prefer ablyof relatively large capacity, and to connect in the leads of the currentsource 13 chokin or inertia coils 12. The control electrode 4 in thiscase is connected to one end of a voltage multiplier coil 7, which .maybe advantageously inductively associated with the coil 8. The other endof the 'coil -7 is preferably connected to one terminal or point onthe-coil 8, either directly or through a condenser 9.

In Figs. 2 and 3, the control electrode 4 located on the inside of thetube acts in the same way to cut off more or less completely at properpoints in the cycle, the flow of current through the gas column. In Fig.4 the control electrodeis placed at one end of the tube outside of thepath of discharge between the two main electrodes 2 and 3, and isconnected to one or the other of the terminals of the oscillatingcircuit, either directly or through the voltage multiplier coil 7, whichis preferably a continuation of the main oscillating coil 8. In thiscase a stopping condenser 9 is inserted in the lead to the electrode 4to insure against the main discharge from passin directly between thecontrol electrode 4 an the main electrode 2 nearest thereto. This isimportant where the control electrode, as will ordinarily be the case,is connected externally to the more remote of the two main electrodes.In Fig. 5 I employ two control electrodes 4, and each of these isconnected through a voltage multiplier or phase retardation coil to thatone of the main electrodes lying furthest therefrom. In Fig. 4 theoscillation circuit comprises the inductance 7, 8, the condenser 10, andthe gas discharge path through the tube, all in series with each other.

I 'find that with the arrangements of rarified gas discharge path,oscillating circuits and control electrodes above described, continuousoscillations of constant amplitude of hi h frequencies suitable for usein radio tel egraph and telephone transmitters, and capable ofgenerating or converting relatively large amounts of direct electricalenergy 1nto alternating electrical energy is afforded. Such arrangementshave a very great advantage over all thermionic tube devices in that noenergy is wasted in heating tlfe-filament or cathode and the life of thetube is indefinite as against a very limited length of life of suchfilament tube. lkVhere large power is thus converted the tube becomeexcessively hot especially in its constricted portion, and I prefertherefore to make the same, or at least the central or constrictedportion thereof, of quartz-glass, or silica, which can withstand a veryhigh temperature without softening or becoming semiconducting, andfurthermore, if desired, any suitable means for cooling the tube or itscentral portion well known in the art such as immersion in water, oil,or by air blast, may be utilized.

In Fig. 6 I have shown a method of control of the gas conducting columnby electromagnetic as distinguished from electrostatic means. Here Isurround the central portion 14 of the tube, or a portion thereof, witha coil of wire 37, which is in circuit, either directly-or byassociation, with the oscillating discharge circuit. A current throughcoil 37 will greatly concentrate or discharge the normal distribution ofthe ionized current conductin gas in the tube, and if such current beapp lied at the proper part of the oscillation cycle, the resistance ofthe gas path to the current flowing therethrough will be greatlyincreased. In addition to this coil 37 carrying an oscillating orperiodic current there may be employed an additional coil 38. Alsosurrounding the tube and through which passes a direct current from anysuitable source, as for example, from a battery 39 or other lowfrequency source, which current is so regulated that the conducting gascolumn in the tube is brought to a more critical or less stablecondition, whereby it is much more readily interrupted or controlled bythe pulsating currents passing through the coil 37 or by the pulsatingE. M. Fs. applied to the control electrode, as for example, in Fig. 1. Imay then place my key, switch, or other suitable signal control device,diagrammatically illustrated in Fig. 5, in this auxiliary'circuit.Otherwise I prefer to control the signal gererationby placing my key,microphone, or other signaling device in the circuit to the controlelectrode or associate it with such circuit in a manner similar to thatnow well known in the oscillating or osci-llion art.

Many modifications and changes in details will readily occur to thoseskilled in the art without departing from the spirit and scope of myinvention as defined in the claims, but having now set forth the objectsand nature of my invention, and having shown and described variousstructures embodying the principles thereof, what I claim as new anduseful and of my own invention and desire to secure by Letters Patentis,-

1. Means for generating sustained alternating currents comprising avessel containing therein two separated cold electrodes, a currentsource for continuously causing a flow of current between said coldelectrodes, and means for causing variations in the flow of currentbetween said cold electrodes, and an oscillating circuit connectedbetween said cold electrodes, said oscillating circuit being independentof said current source so that the varying current generated does notpass through said source.

2. Means for generating sustained alter-- nating currents comprising avessel containing therein two separated cold electrodes, with a gaseousconducting space therebetween, a current source for causing a continuousflow of current between said electrodes, and means for causingvariations in the flow of current between said electrodes, and anoscillating circuit connected between said electrodes, said oscillatingcircuit, being independent of said current source.

3. Means for generating sustained alternatin currents comprising avessel containing therein two separated cold electrodes, with asectionally restricted conducting space therebetween, means for causin acontinuous flow of current between said electrodes, and means forcausing variations in the flow of current between said electrodes, andan oscillating circuit connected between said electrodes.

4. Means for generating sustained alternating currents comprising avessel containing therein two separated cold electrodes, a currentsource for'continuously causing a flow of current between said coldelectrodes, and means including a control electrode for causingvariations in the flow of current between said electrodes, and anoscillating circuit connected to all of said electrodes said oscillatingcircuit being independent 0t said current source so that the varyingcurrent generated does not pass through said source.

5. Means for generating sustainedalternating currents comprising avessel containing therein two separated cold electrodes, with a gaseousconducting space therebetween, a current source for causing a continuousflow of current between said electrodes, and means including a controlelectrode for causing variations in the flow of" current between saidelectrodes, and an oscillating circuit connected to all of saidelectrodes, said oscillating circuit being independent of said currentsource so that the varying current generated does not pass through saidsource.

6. Means for generating sustained alternating currents comprising avessel containing therein two separated cold electrodes, with asectionally restricted conducting space therebetween, means for causinga continuous flow of current between said electrodes, and'meansincluding a control electrode for periodically disturbing the flow ofcurrent between said electrodes, and an oscillating circuit connected toall of said electrodes.

7. Means for generating sustained alternating currents comprising avessel containing therein two separated cold electrodes, with asectionally restricted conducting space therebetween, means for causinga continuous flow of current between said electrodes, and meansincluding a control electrode positioned adjacent the sectionallyrestricted portion of the said conducting space between the electrodesfor periodically disturbing the flow of current between said electrodes,and an oscillating circuit connected to all of said electrodes.

8. Means for generating sustained alternating currents comprising avessel containing therein two separated cold electrodes with asectionally restricted conducting space therebetween, means for causin acontinuous flow of current between sai electrodes, and-means including acontrol electrode positioned adjacent the restricted portion of the saidconducting space and within the vessel for periodically disturbing theflow of current between said electrodes, and an oscillating circuitconnected to all of said electrodes.

9. Means for generating sustained alternating currents comprising avessel containing therein two separated cold. electrodes with a gaseousconducting space therebetween, a current source for causing a continuousflow of current between said electrodes, and means including a controlelectrode enclosed within said vessel for periodically disturbing theflow of current In testimony whereof I have hereunto set my hand on this30th day of September,

- WM. E. GABITY.

generated does not pass through said source.

